How many chapters are in ecclesiastes's in the original bible?

There are twelve chapters of Ecclesiastes. Not sure what you mean by "original" Bible, but you're probably referring to the Codex Vaticanus of Constantine which was one of the first to combine the old and new Testaments, and eventually became what we now call the Catholic Bible. Since, what was then the canonical Hebrew Bible was used as the Old Testament, and it contained twelve chapters of Ecclesiastes, I would say the answer is still twelve.